Thanks for the photo of neck-heel, well ? 7 digit S/N could be correct for 1978 Springy, but I can?t tell any more without seeing the rest of the guitar.
As far as the second guitar is concerned (sounds like you?re buying?) ? a lot of guys used to scratch the Tokai decals off (not any more!), but you can buy a replacement for about $20. According to the Registry ?5 digit number on neck plate just means it?s an ST50 or 60 and copy of US Strat?s made from 1956-60.
Re. the nut & saddles ? obvious answer I know, but - if you just want the guitar as a ?player? (as opposed to collectable), then they?re fine as long as they work OK. However, the cheap/light trem-block may mean the guitar goes out of tune easily if your trying Jeff Beck type dive-bombs.
7okai Springys are getting quite expensive now, although there are still plenty around (eg eBay) and bargains do turn up from time to time. So you can get one without any issues if you you?re prepared to wait or pay a bit more (always cheaper after Christmas lol). 2cents :-? .
Ian.